Book/Report

FZJ-2017-02641

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Kugeltechniken zur Messung von Flussdichte und Dosisleistungen thermischer, intermediärer und schneller Neutronen

Nachtigall, D.FZJ* ; Rohloff, F.FZJ*

1964
Kernforschungsanlage Jülich, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/14135

Report No.: Juel-0213-ST

Abstract: From the point of view of Radiation Protection it is important to know the following quantities in a neutron field: flux density, energy doserate, doserate equivalent.Its measuring in the whole energy range of interest ($10^{-2} - 10^{7}$eV) is a problem up to now. The neutron scintillation counter after BRAMBLETT, EWING and BONNER with LiJ(Eu) crystal and polyethylene spheres is very useful for these purposes. By the help of a three sphere combination (2$^{\shortparallel}$, 3 1/2$^{\shortparallel}$ and 11$^{\shortparallel}$ diameter) and summering up the countrates taken with the three spheres, neutron flux densities in the energy range from 0.5 eV up to 7 • 10$^{6}$ eV can be measured omnidirectional and independent from neutron energy. A two sphere technique (2 1/4$^{\shortparallel}$ and 11 3/4$^{\shortparallel}$ diameter) with weight factors approximates the neutron energy dose curve in the range from 10$^{-2}$ eV up to 7 • 10$^{6}$ eV.Another three sphere combination (5$^{\shortparallel}$ , 7$^{\shortparallel}$ and 12$^{\shortparallel}$ diameter) and weight factors give a measurement of the neutron doserate equivalent in the range from 0.5 eV up to 7 · 10$^{6}$ eV. A biological dose curve considering quality factors after BOND and BATEMAN can also be approximated between 10$^{-2}$ eV and 7 · 10$^{6}$ eV by a three sphere combination (2$^{\shortparallel}$, 4$^{\shortparallel}$ and 7$^{\shortparallel}$ diameter) and weight factors. Later changes of quality factors can be regarded by approximations with other sphere combinations. In order to obtain the four termed quantities, 9 different measurements with the help of 9 different sphere diameters are necessary. The procedure, however, can be optimalized. By the help of 5 measurements with 5 different sphere diameters (2$^{\shortparallel}$, 3 1/2$^{\shortparallel}$. 5$^{\shortparallel}$. 7$^{\shortparallel}$ and 11 1/2$^{\shortparallel}$ diameter) and using weight factors the same four quantities in the range from 10$^{-2}$ eV up to 10$^{7}$ eV and the average energy can be obtained. Besides LiJ(Eu)-crystals all detectors operating with the Li$^{6}(n, \alpha)$-reaction are practicable, especially LiF thermoluminescent detectors.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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Database coverage:

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